Pneumatic door closer

ABSTRACT

PISTON MEANS IN A PNEUMATIC DOOR CLOSER AND INCLUDING A BODY DEFINING A RADIALLY OUTWARDLY OPENING ANNULAR CHANNEL HAVING AXIALLY SPACED SIDEWALLS, A SEALING RING MOVABLE AXIALLY TOWARD AND AWAY FROM ONE OF THE SIDEWALLS, AND A POROUS LUBRICATING RING DISPOSED BETWEEN THE OTHER OF THE SIDEWALLS AND THE SEALING RING. BOTH RINGS FRICTIONALLY ENGAGE THE CYLINDRICAL SURFACE OF AN ELONGATED CASING IN WHICH THE PISTON MEANS IS AXIALLY MOVABLE. THE PISTON MEANS INCLUDES A PAIR OF COOPERATING ELEMENTS WELDED TOGETHER AND TO THE INNER END OF A PLUNGER ROD WHICH EXTENDS AXIALLY OUTWARDLY OF ONE END OF THE CASING.

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United States Patent 27,714 PNEUMATIC DOOR CLOSER Russell W. Waldo, St.Paul, Minn., assignor to Ideal Security Hardware Corp., St. Paul, Minn.Original No. 3,593,367, dated July 20, 1971, Ser. No. 850,578, Aug. 15,1969. Application for reissue Mar. 1, 1972, Ser. No. 231,036

Int. Cl. E051 3/00 US. CI. 1666 8 Claims Matter enclosed in heavybrackets appears in the original patent but forms no part of thisreissue specification; matter printed in italics indicates the additionsmade by reissue.

ABSTRACT OF THE DISCLOSURE Piston means in a pneumatic door closer andincluding a body structure defining a radially outwardly opening annularchannel having axially spaced sidewalls, a sealing ring movable axiallytoward and away from one of the sidewalls, and a porous lubricating ringdisposed between the other of the sidewalls and the sealing ring. Bothrings frictionally engage the cylindrical surface of an elongated casingin which the piston means is axially movable. The piston means includesa pair of cooperating elements welded together and to the inner end of aplunger rod which extends axially outwardly of one end of the casing.

BACKGROUND OF THE INVENTION Heretofore, pneumatic door closers of thepiston-cylinder type have utilized various lubricating devices, such asoil-soaked sleevelike wicks more or less loosely contained in thecylinders, for coating the cylinder wall and moving parts of the closerswith oil or other lubricant. One such arrangement is disclosed in US.Pat. No. 2,646,589 to Bert A. Quinn. Lubricating devices of this generaltype depend upon capillary action and they do not always coat theinterior cylinder wall surface of the casing uniformly. Further, pistonstructures in pneumatic door closers, heretofore produced have beenturned from metal bar stock, or die-cast, and have been relatively heavyand costly to produce and assemble.

SUMMARY OF THE INVENTION The piston structure of this inventioncomprises a pair of cooperating piston body elements inexpensivelyformed from sheet metal welded to each other and to the inner end of acooperating plunger rod at a single point or small area to provide arigid lightweight assembly. One of the body elements is in the nature ofa generally disclike washer and is formed to provide a flat radial wall,the other element being generally cup shaped and formed with a generallyconical wall providing a seat, and a central hollow boss, the conicalwall diverging radially outwardly with respect to the flat wall of thewasher element. The hollow boss receives the inner end of the plungerrod, and is formed with an end wall having a convex surface abutting theinner end of the plunger rod, the opposite of the end wall beingconcave. The disclike washer element is formed to provide a centraldimple having a convex surface abutting the concave surface of the bossend wall, and circumferentially spaced tabs projecting in one directionand fitting over the hollow boss and other circumferentially spaced tabsprojecting axially in the opposite direction for engagement with one endof the casing to limit movement of the piston means toward said one endof the casing. The piston structure further includes a sealing ringdisposed generally concentrically between the piston body element inclosely fitting axial sliding engagement with the cylinder wall of thecasing and movable toward and away from seating en- Reissued July 31,1973 gagement with the conical seating surface; and a porouslubricant-saturated lubricating ring disposed between the sealing ringand the washer element in concentric wiping engagement with the cylinderwall of the casing, whereby lubricant is applied directly to the casingwall over the length thereof traversed by the piston structure. Thedisclike element is further formed to provide a plurality of airpassages therethrough radially inwardly relative to the sealing andlubricating rings, flange means extending in one direction totelescopically receive the hollow boss, and stop means projecting in theopposite direction for engagement with the adjacent end of the casing tolimit movement of the piston means and plunger rod toward the adjacentend of the casing.

DESCRIPTION 0 FTHE DRAWINGS FIG. 1 is a view partly in top plan andpartly in section, showing the pneumatic door closer of this inventionmounted to a doorframe and to a door hingedly mounted in the doorframc;

FIG. 2 is an enlarged fragmentary section taken substantially on theline 2-2 of FIG. 1;

FIG. 3 is a still further enlarged fragmentary section correspondinggenerally to a portion of FIG. 2;

FIG. 4 is a view in end elevation of a disclike washer element of thisinvention as viewed from the left to the right with respect to FIGS. 2and 3; and

FIG. 5 is a view of the washer element of FIG. 4 as seen from theopposite side thereof.

DETAILED DESCRIPTION In FIG. 1, a doorframe is shown as including adoorsill 1, laterally spaced generally vertically disposed door-framemembers 2 and 3, and stop strips 4 and 5 thereon. Inner and outer doors6 and 7 are hingedly secured to the doorframe member 2, as indicated at8 and 9 respectively. For the purpose of the present example, it may beassumed that the door 7 is an outer screen or storm door, with which thepresent door closer is particularly adapted for use.

The present door closer comprises; an elongated tubular casing 8 havingan inner cylindrical wall surface 9, a closure member 10 at one end ofthe casing l, and a bushing element 11 at the opposite end thereof; aplunger rod 12 extending axially within the casing 8 and projectingoutwardly through the bushing 11; piston means mounting the inner end ofthe plunger rod 12 and indicated generally at 13; a mounting bracket 14pivotally secured to the outer end 15 of the plunger rod 12, by means ofa pivot pin or the like 16; and a second bracket 17. As shown in FIG. 1,the bracket 14 is adapted to be secured to the stop strip 4 and framemember 2, the bracket 17 being rigidly secured to the door 7. Theclosure member 10 is provided with an annular cup-shaped portion 18, thebracket 17 being formed to provide hook portions 19 by means of whichthe closure member 10 is secured to the bracket 17. The plunger rod 12is urged in a door closing direction longitudinally of the casing 8 by acoil compression spring 20 interposed between the piston means 13 andthe bushing 11, and a smaller coil compression snubber spring 21 isloosely wound on the plunger rod 12 between the piston means 13 andbushing 11. The snubber spring 21 is of substantially less axial lengththan the spring 20, and cushions shock load on the door closer, when thedoor is swung violently toward its full open position. The closuremember 10 is provided with a screw-threaded axial opening 22 forreception of a slotted screw 23 for adjustably admitting air to theinterior of the casing 8 between the closure member 10 and piston means13 and for permitting escape of air outwardly therefrom, in the usualmanner, moves into engagement with the lubricating ring 39.

The piston means 13 comprises body structure including a disclike washerelement 24 and a generally cupshaped valve seat element 25, the disclikewasher element having a radially fiat annular surface 26 in axiallyspaced opposed relationship to a generally conical valve seat surface 27on the valve seat element 25, the surface 27 diverging in a directionradially outwardly with respect to the annular surface 26 andcooperating therewith to provide a radially outwardly opening channel28. The valve seat element is formed to provide a marginal skirt orflange 29 that projects toward the end of the casing 9 containing thebushing 11. With reference to FIG. 3, it will be seen that the outerdiameters of the skirt 29 and washer element 24 are somewhat less thanthe diameter of the cylindrical casing surface 9, so that air ispermitted to pass freely therebetween.

At its central portion, the valve seat element 25 is formed to provide ahollow boss 30 having an end wall 31, for reception of the adjacentinner end of the plunger rod 12. As shown in FIG. 3, the end wall 31 isformed to define a convex surface 32 which abuts the adjacent end of theplunger rod 12, the opposite side of the end wall 31 being concave. Atits central portion, the Washer element 24 is formed to provide a dimple33 having a convex surface 34 that at least partially engages theadjacent concave surface of the end Wall 31. It will be noted that theradius of the convex dimple surface 34 is smaller than that of theadjacent concave surface of the end wall 31, so that there issubstantially point contact thcrebetween. It will be further noted, withreference to FIG. 3 that the adjacent end of the plunger rod 12 is flatso that there is substantially point contact between the inner end ofthe plunger rod 12 and the convex surface 32 of the end wall 31.Radially outwardly of the dimple 33, the washer element 25 is pierced toprovide a plurality of circumferen tially spaced air passages 35therethrough and formed to provide flange means in the nature of aplurality of circumferentially spaced tabs or ears 36 thattelescopically receive the hollow boss 30 of the valve seat element 25to axially align the washer element 24 with the valve seat element 25,Other tabs 37 are punched from given ones of the openings 35 in adirection axially opposite the tabs 36, and are engageable with theclosure member 10 to limit movement of the piston means 13 in adoor-closing direction toward the closure member 10. It will be noted,with reference to FIGS. 3-5, that the tabs 37 are disposed alternatelywith respect to the tabs 36, the tabs 37 eifectively preventing theradially outer portions of the washer element 24 from impinging on theclosure member 10 whereby to prevent possible warping of the washerelement 24.

The tabs 36 and hollow boss 30 accurately hold the washer element 24,seating element 25 and plunger rod 12 in their relative positions duringassembly, wherein these parts are permanently joined together,preferably by resistance welding at the points of contact therebetweenon the common axis thereof, as shown in FIG. 3.

A sectionally circular sealing ring 38, of rubber or other suitableelastic material is disposed within the annular channel 28 concentricwith the cylindrical surface 9 of the casing 8. The sealing ring 38preferably has an outer diameter to snugly slidably fit the surface 9,and is disposed adjacent the conical surface 27 of the valve seatelement 25, so as to have sealing engagement therewith. Across-sectionally circular lubricating ring 39 is also disposed in thechannel 28 between the sealing ring 38 and the washer element 24, thelubricating ring 39 also being of a diameter to snugly slidably fit theinner surface 9 of the casing 8. As shown in FIG. 3, the combined axialdimension of the rings 38 and 39 is slightly less than the axialdimension of the annular groove 28 at the point where the sealing ring38 seatingly engages the conical surface 27 of the valve seat element25. The lubricating ring 39 is made from felt or other suitable porousmaterial, and is soaked with oil or similar lubricant, so that uponaxial movement of the piston means 13 within the casing 8, the greaterportion of the length of the cylindrical surface 9 will be lubricatedthereby, each time the door 7 is opened and closed.

With reference to FIGS. 2 and 3, it will seen that the spring 20, beingcontained at one end within the marginal flange or skirt 29 of the valveseat element 25, and at its other end within a skirtlike portion 40 ofthe bushing 11, is at least partially held against contact with theinner cylindrical casing surface 9 to insure smoothness of operation.Should the longitudinally intermediate portion of the spring 20 becomearched or bowed so that some of the convolutions thereof come intocontact with the inner casing surface 9 during opening and closingmovements of the door 7, these casing-surface engaging convolutions willslide easily and smoothly over the casing surface 9 due to the coatingof lubricant applied thereto by the lubricating ring 39.

Due to the above-mentioned differential between the combined axialdimensions of the sealing rings 38 and 39 and the portions of the groove28 engaged thereby, a predetermined lost motion is obtained between therings 38-39 and the piston elements 24-25 during reversal ofrcciprocatory movement of the piston means 13. It will be noted that thepassages 35 are disposed radially inwardly of the rings 38 and 39 topermit free passage of air through the passages 35 from one side of thewasher element 24 to the other thereof. During opening movements of thedoor, the plunger rod 12 and piston means 13 move from the left to theright with respect to FIGS. 2 and 3 relative to the casing 8. During theinitial portion of such movement, the valve seat element 25 moves out ofengagement with the sealing ring 38, and the washer element 24 movesinto engagement with the lubricating ring 39. As such door-openingmovement continues, air within the cylinder chamber indicated at A movesbetween the cylindrical surface 9 and skirt 29, generally radiallyinwardly between the conical surface 25 and sealing ring 38, and axiallythrough the passages 35 to a cylinder chamber B between the piston means13 and closure member 10. This movement of air from the cylinder chamberA to the cylinder chamber B is quite free, permitting the door 7 to berelatively easily opened, substantially the only load againstdoor-opening movement being applied by compression of the spring 20.Then, when the door 7 is released for closing, the spring 20 urges theplunger rod 12 and piston means 13 relatively toward the closure member10, initial door-closing movements causing the conical surface 27 tomove into sealing engagement with the sealing ring 38, thus effectivelyclosing off passage of air from the cylinder chamber B to the cylinderchamber A. After sealing contact is made between the sealing ring 38 andconical seating surface 27, air escapes from the cylinder chamber Boutwardly through the metered opening 22 at a predetermined rate offlow.

With the above-described construction, I have provided a door closerthat is simple and inexpensive to fabricate and assemble and which isquiet and smooth in operation. The lubricating ring 39, having a greatercircular cross section than the sealing ring 38, tends to hold thesealing ring 38 radially outwardly against the cylindrical wall surface9 during door-closing movement of the piston means 13, the thickness oflubricating ring 39 enabling the same to hold sufficient lubricant toproperly lubricate the wall surface 9 over greatly extended periods oftime.

What I claim is:

1. A pneumatic door closer comprising:

(a) an elongated casing having an inner cylindrical wall surface, aclosure member at one end, and an axial opening at its other end;

(b) a plunger rod extending axially through said axial opening formovements axially of said casing and having inner and outer endsrespectively within and axially outwardly of said casing;

(c) means on said plunger rod outer end and said closure member forconnection one to a door frame and the other to a door hingedly mountedin the doorframe;

(d) piston means on the inner end of said plunger rod comprising:

(1) body structure including a disclilte washer element having a Hatradial wall portion and air passage means extending in a directionaxially therethrough, and a generally cup-shaped valve seat elementhaving a conical wall portion diverging radially outwardly with respectto said flat radial wall portion and defining therewith a radiallyoutwardly opening annular channel, the body structure having radiallyouter marginal portions inwardly spaced from said cylindrical wallsurface, said washer element being disposed between said valve seatelement and said closure member;

(2) a sealing ring in said channel concentric with and in close fittingsliding engagement with said inner cylindrical wall surface and movabletoward and away from sealing engagement with said conical wall portion;

(3) and a porous lubricating ring in said channel in closely fittingsliding engagement with said cylindrical wall surface axially adjacentsaid sealing ring and positioned to engage said fiat radial wallportion;

(4) said channel having an axial dimension greater than the combinedaxial dimension of said sealing and lubricating rings to permit limitedaxial movement of said body structure relative to said rings (e) andyielding means in said casing urging said piston means and plunger rodin a door-closing direction toward said closure member;

(f) said valve element being formed to provide an axial hollow bossdefining a recess for reception of the inner end of valve seat plungerrod, said inner end of the plunger rod and said washer being welded tosaid boss.

2. The door closer defined in claim 1 in which said washer elementincludes axially projecting flange means telescopically received oversaid boss to axially align said washer element with said valve seatelement.

3. The door closer defined in claim 2 in which said washer elementincludes stop lug means projecting in an axial direction opposite saidflange means for engagement with said closure member to limit movementof said plunger rod and piston means in a door-closing direction towardsaid closure member.

4. The door closer defined in claim 2 in which said hollow boss includesa closed end wall having a convex surface engaging the adjacent end ofsaid plunger rod and an opposite concave surface facing said washerelement, said washer element having a central dimple having a convexsurface engaging the concave surface of said closed end wall, saidwasher element, sealing element and the adjacent end of said plunger rodbeing welded together at said dimple and said convex and concavesurfaces of said end wall of the boss 5. The door closer defined inclaim 4 which said convex dimple surface has a radius of curvature lessthan that of the adjacent concave surface of said boss end wall toprovide a substantially point contact therebetween.

6. The door closure defined in claim 3 in which said washer element isformed from sheet metal, said flange means comprising a plurality ofcircumferentially spaced tabs sheared and bent from said washer elementin one direction axially thereof to provide portions of said air passagemeans, said stop lug means comprising a plurality of circumferentiallyspaced tabs sheared and bent from said washer element in the oppositedirection axially thereof each alternately with a different one of saidfirstmentioned tabs to provide other portions of said air passage means.

7. A pneumatic door closer comprising:

(a) an elongated casing having an inner cylindrical wall surface, aclosure member at one end, and an axial opening at its other end;

(b) a plunger rod extending axially through said axial opening formovements axially of said casing and having inner and outer endsrespectively within and axially outwardly of said casing;

(c) means on said plunger rod outer end to said closure member forconnection one to a doorframe and the other to a door hingedly mountedin the doorframe;

(c) means on said plunger rod outer end and said clocomprising:

(l) body structure defining a radially outwardly opening annular channelhaving a fiat radial wall and a generally conical wall axially spacedfrom and diverging radially outwardly from said flat radial wall, saidflat radial wall having air passage means extending in a directionaxially therethrough from said channel, said body structure havingradially outer marginal portions inwardly spaced from said cylindricalwall surface;

(2) a sealing ring disposed in said channel in closely fitting slidingengagement with said inner cylindrical wall surface and for axialmovements relative to said body structure toward and away from axialabutment with said generally conical wall;

(3) and a porous lubricating ring in said channel in closely fittingsliding engagement with said inner cylindrical wall surface, saidlubricating ring being disposed for axial movements between axiallyabutting relation with said sealing ring and said flat radial Wall;

(4) said channel having an axial dimension greater than the combinedaxial dimension of said sealing and lubricating rings to permit limitedaxial movement of said body structure relative to said rings;

(e) and yielding means in said casing urging said piston means andplunger rod in a door-closing direction toward said closure member.

8. A pneumatic door closer comprising:

(a) an elongated casing having an inner cylindrical wall surface, aclosure member at one end, and an axial opening at its other end;

(b) a plunger rod extending axially through said axial opening formovement axially of said casing and having inner and outer endsrespectively within and axially outwardly of said casing;

(0) means on said plunger rOd outer end and said closure member forconnection one to a doorframe and the other to a door hingedly mountedto the doorframe;

(d) piston means on the inner end of said plunger r d comprising:

(1) body structure defining a radially outwardly opening annular channelhaving a flat radial wall and a generally conical wall axially spacedfrom and diverging radially outwardly from said flat radial wall, saidflat radial wall being arranged to provide passage means extending in adirection axially from said channel, said body structure having radiallyouter marginal portions inwardly spaced from said cylindrical wallsurface;

(2) a sealing ring disposed in said channel in closely fitting slidingengagement with said inner cylindrical wall surface and for axialmovements relative to said body structure toward and away from axialabutment with said generally conical wall;

27,714 7 8 (3) and a porous lubricating ring in said channel ReferencesCited in Closely fitting sliding engagement with said The followingreferences, cited by the Examiner, are

'l 2 sllrfacf, said hbrlm'ing of record in the patented file of thispatent or the original rmg being disposed for anal movements be- Patenttween axially abutting relation with said sealing ring and said flatradial wall; 0 UNITED i PATENTS (4) said channel having an axialdimension greater 3,131,420 5/1964 Qufnn 16'56 than the combined axialdimension of said seal- $158,894 12/1964 Qulnn 1666 ing and lubricatingrings to permit limited axial movement of said body structure relativeto said FRANCIS ZUGEL Primary Examiner 1L) rings; P. A. ASCHENBRENNER,Assistant Examiner (e) and yielding means in said casing urging saidpiston means and plunger rod in a door-closing direction US. Cl. X.R.

toward said closure member. 652

